THE OPEN SEA 77 
for part of their life and at home elsewhere 
at another period. Thus the guillemots and 
puffins, which nest in early summer in such 
vast numbers on some of the British bird- 
cliffs, are open-sea birds for a considerable 
part of the year. Many shore animals, such 
as crab and rock-lobster, star-fish and sea- 
urchin, have free-swimming larve in the open 
water, often many miles from the coast. Jelly- 
fishes are characteristically open-sea animals, 
their stranding on flat beaches being quite 
accidental, but it should be noticed that the 
common and cosmopolitan jelly-fish, durelia 
aurita, passes through a juvenile fixed stage, 
attached to rock or seaweed. 
THE WHALE AS A GREAT BUNDLE OF 
FITNESSES 
The mammals of the open sea are the 
Cetaceans, giants like the Right Whale and 
the Sperm Whale, and small ones like dol- 
phins and porpoises. All of them have such 
mastery of their medium that they must be 
ranked among the conquerors of the open sea. 
Let us think for a little of the whale as a 
great bundle of fitnesses, taking especially the 
